// Query all the entries from the AspNet_SqlCacheTablesForChangeNotification
// table and update the values in the cache accordingly.
//
// This is mainly called by the timer callback. But will also be called by
// UpdateDatabaseNotifState, which polls for changes on demand.
internal static void PollDatabaseForChanges(DatabaseNotifState dbState, bool fromTimer) {
SqlDataReader sqlReader = null;
SqlConnection sqlConn = null;
SqlCommand sqlCmd = null;
int changeId;
string tableName;
CacheInternal cacheInternal = HttpRuntime.CacheInternal;
string monitorKey;
object obj;
bool notifEnabled = false;
Exception pollExpt = null;
SqlException sqlExpt = null;
Debug.Trace("SqlCacheDependencyManagerPolling",
"PollCallback called; connection=" + dbState._connectionString);
if (s_shutdown) {
return;
}
// If this call is from a timer, and if the refcount for this database is zero,
// we will ignore it. The exception is if dbState._init == false,
// which means the timer is polling it for the first time.
if (dbState._refCount == 0 && fromTimer && dbState._init ) {
Debug.Trace("SqlCacheDependencyManagerPolling",
"PollCallback ignored for " + dbState._database + " because refcount is 0");
return;
}
// Grab the lock, which allows only one thread to enter this method.
if (Interlocked.CompareExchange(ref dbState._rqInCallback, 1, 0) != 0) {
// We can't get the lock.
if (!fromTimer) {
// A non-timer caller will really want to make a call to SQL and
// get the result. So if another thread is calling this, we'll
// wait for it to be done.
int timeout;
HttpContext context = HttpContext.Current;
if (context == null) {
timeout = 30;
}
else {
timeout = Math.Max(context.Timeout.Seconds / 3, 30);
}
DateTime waitLimit = DateTime.UtcNow.Add(new TimeSpan(0, 0, timeout));
for (;;) {
if (Interlocked.CompareExchange(ref dbState._rqInCallback, 1, 0) == 0) {
break;
}
Thread.Sleep(250);
if (s_shutdown) {
return;
}
// only apply timeout if a managed debugger is not attached
if (!System.Diagnostics.Debugger.IsAttached && DateTime.UtcNow > waitLimit) {
// We've waited and retried for 5 seconds.
// Somehow PollCallback haven't finished its first call for this database
// Assume we cannot connect to SQL.
throw new HttpException(
SR.GetString(SR.Cant_connect_sql_cache_dep_database_polling, dbState._database));
}
}
}
else {
// For a timer callback, if another thread is updating the data for
// this database, this thread will just leave and let that thread
// finish the update job.
Debug.Trace("SqlCacheDependencyManagerPolling",
"PollCallback returned because another thread is updating the data");
return;
}
}
try {
try {
// Keep a count on how many threads are polling right now
// This counter is used by Dispose()
Interlocked.Increment(ref s_activePolling);
// The below assert was commented out because this method is either
// called by a timer thread, or thru the SqlCacheDependencyAdmin APIs.
// In the latter case, the caller should have the permissions.
//(new SqlClientPermission(PermissionState.Unrestricted)).Assert();
dbState.GetConnection(out sqlConn, out sqlCmd);
sqlReader = sqlCmd.ExecuteReader();
// If we got stuck for a long time in the ExecuteReader above,
// Dispose() may have given up already while waiting for this thread to finish
if (s_shutdown) {
return;
}
// ExecuteReader() succeeded, and that means we at least have found the notification table.
notifEnabled = true;
// Remember the original list of tables that are enabled
Hashtable originalTables = (Hashtable)dbState._tables.Clone();
while(sqlReader.Read()) {
tableName = sqlReader.GetString(0);
changeId = sqlReader.GetInt32(1);
Debug.Trace("SqlCacheDependencyManagerPolling",
"Database=" + dbState._database+ "; tableName=" + tableName + "; changeId=" + changeId);
monitorKey = GetMoniterKey(dbState._database, tableName);
obj = cacheInternal[monitorKey];
if (obj == null) {
Debug.Assert(!dbState._tables.ContainsKey(tableName),
"DatabaseNotifStae._tables and internal cache keys should be in-[....]");
Debug.Trace("SqlCacheDependencyManagerPolling",
"Add Database=" + dbState._database+ "; tableName=" + tableName + "; changeId=" + changeId);
cacheInternal.UtcAdd(monitorKey, changeId, null,
Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration,
CacheItemPriority.NotRemovable, null);
dbState._tables.Add(tableName, null);
}
else if (changeId != (int)obj) {
Debug.Assert(dbState._tables.ContainsKey(tableName),
"DatabaseNotifStae._tables and internal cache keys should be in-[....]");
Debug.Trace("SqlCacheDependencyManagerPolling",
"Change Database=" + dbState._database+ "; tableName=" + tableName + "; old=" + (int)obj + "; new=" + changeId);
// ChangeId is different. It means some table changes have happened.
// Update local cache value
cacheInternal.UtcInsert(monitorKey, changeId, null,
Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration,
CacheItemPriority.NotRemovable, null);
}
originalTables.Remove(tableName);
}
// What's left in originalTables are the ones that're no longer
// contained in the AspNet_SqlCacheTablesForChangeNotification
// table in the database.
// Remove tables which are no longer enabled for notification
foreach(object key in originalTables.Keys) {
dbState._tables.Remove((string)key);
cacheInternal.Remove(GetMoniterKey(dbState._database, (string)key));
Debug.Trace("SqlCacheDependencyManagerPolling",
"Remove Database=" + dbState._database+ "; key=" + key);
}
// Clear old error, if any.
if (dbState._pollSqlError != 0) {
dbState._pollSqlError = 0;
}
}
catch (Exception e) {
pollExpt = e;
sqlExpt = e as SqlException;
if (sqlExpt != null) {
Debug.Trace("SqlCacheDependencyManagerPolling", "Error reading rows. SqlException:"+
"\nMessage=" + sqlExpt.Message +
"\nNumber=" + sqlExpt.Number);
dbState._pollSqlError = sqlExpt.Number;
}
else {
dbState._pollSqlError = 0;
Debug.Trace("SqlCacheDependencyManagerPolling", "Error reading rows. Exception:"+ pollExpt);
}
}
finally {
try {
if (sqlReader != null) {
sqlReader.Close();
}
dbState.ReleaseConnection(ref sqlConn, ref sqlCmd, pollExpt != null);
}
catch {
}
// Need locking because EnsureTableIsRegisteredAndPolled() assumes
// the fields in a dbState are set atomically.
lock(dbState) {
dbState._pollExpt = pollExpt;
// If we have changed from being enabled to disabled, and
// it's because we cannot find the SP for polling, it means
// the database is no longer enabled for sql cache dependency.
// we should invalidate all cache items depending on any
// table on this database
if (dbState._notifEnabled && !notifEnabled &&
pollExpt != null && dbState._pollSqlError == SQL_EXCEPTION_SP_NOT_FOUND) {
foreach(object key in dbState._tables.Keys) {
try {
cacheInternal.Remove(GetMoniterKey(dbState._database, (string)key));
}
catch {}
Debug.Trace("SqlCacheDependencyManagerPolling",
"Changed to disabled. Remove Database=" + dbState._database+ "; key=" + key);
}
// Since we have removed all the cache items related to this database,
// the _refCount of this database will drop to zero, and thus the timer
// callback will not poll this database.
// So we have to cleanup _tables now.
dbState._tables.Clear();
}
dbState._notifEnabled = notifEnabled;
dbState._utcTablesUpdated = DateTime.UtcNow;
Debug.Trace("SqlCacheDependencyManagerPolling", "dbState:_pollExpt="+ dbState._pollExpt +
"; _pollSqlError=" + dbState._pollSqlError + "; _notifEnabled=" + dbState._notifEnabled +
"; __utcTablesUpdated=" + dbState._utcTablesUpdated);
}
// Mark dbState as initialized by PollCallback for the first time.
// EnsureTableIsRegisteredAndPolled() depends on this.
if (dbState._init != true) {
dbState._init = true;
}
Interlocked.Decrement(ref s_activePolling);
// Release the lock
Interlocked.Exchange(ref dbState._rqInCallback, 0);
}
}
catch { throw; } // Prevent Exception Filter Security Issue (ASURT 122835)
}
internal static void PollDatabaseForChanges(DatabaseNotifState dbState, bool fromTimer)
{
SqlDataReader reader = null;
SqlConnection sqlConn = null;
SqlCommand sqlCmd = null;
CacheInternal cacheInternal = HttpRuntime.CacheInternal;
bool flag = false;
Exception exception = null;
SqlException exception2 = null;
if (s_shutdown)
{
return;
}
if (((dbState._refCount == 0) && fromTimer) && dbState._init)
{
return;
}
if (Interlocked.CompareExchange(ref dbState._rqInCallback, 1, 0) != 0)
{
int num2;
if (fromTimer)
{
return;
}
HttpContext current = HttpContext.Current;
if (current == null)
{
num2 = 30;
}
else
{
num2 = Math.Max(current.Timeout.Seconds / 3, 30);
}
DateTime time = DateTime.UtcNow.Add(new TimeSpan(0, 0, num2));
do
{
if (Interlocked.CompareExchange(ref dbState._rqInCallback, 1, 0) == 0)
{
goto Label_00EA;
}
Thread.Sleep(250);
if (s_shutdown)
{
return;
}
}
while (Debugger.IsAttached || (DateTime.UtcNow <= time));
throw new HttpException(System.Web.SR.GetString("Cant_connect_sql_cache_dep_database_polling", new object[] { dbState._database }));
}
Label_00EA:
try
{
try
{
Interlocked.Increment(ref s_activePolling);
dbState.GetConnection(out sqlConn, out sqlCmd);
reader = sqlCmd.ExecuteReader();
if (!s_shutdown)
{
flag = true;
Hashtable hashtable = (Hashtable) dbState._tables.Clone();
while (reader.Read())
{
string table = reader.GetString(0);
int num = reader.GetInt32(1);
string moniterKey = GetMoniterKey(dbState._database, table);
object obj2 = cacheInternal[moniterKey];
if (obj2 == null)
{
cacheInternal.UtcAdd(moniterKey, num, null, Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration, CacheItemPriority.NotRemovable, null);
dbState._tables.Add(table, null);
}
else if (num != ((int) obj2))
{
cacheInternal.UtcInsert(moniterKey, num, null, Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration, CacheItemPriority.NotRemovable, null);
}
hashtable.Remove(table);
}
foreach (object obj3 in hashtable.Keys)
{
dbState._tables.Remove((string) obj3);
cacheInternal.Remove(GetMoniterKey(dbState._database, (string) obj3));
}
if (dbState._pollSqlError != 0)
{
dbState._pollSqlError = 0;
}
}
}
catch (Exception exception3)
{
exception = exception3;
exception2 = exception3 as SqlException;
if (exception2 != null)
{
dbState._pollSqlError = exception2.Number;
}
else
{
dbState._pollSqlError = 0;
}
}
finally
{
try
{
if (reader != null)
{
reader.Close();
}
dbState.ReleaseConnection(ref sqlConn, ref sqlCmd, exception != null);
}
catch
{
}
lock (dbState)
{
dbState._pollExpt = exception;
if ((dbState._notifEnabled && !flag) && ((exception != null) && (dbState._pollSqlError == 0xafc)))
{
foreach (object obj4 in dbState._tables.Keys)
{
try
{
cacheInternal.Remove(GetMoniterKey(dbState._database, (string) obj4));
}
catch
{
}
}
dbState._tables.Clear();
}
dbState._notifEnabled = flag;
dbState._utcTablesUpdated = DateTime.UtcNow;
}
if (!dbState._init)
{
dbState._init = true;
}
Interlocked.Decrement(ref s_activePolling);
Interlocked.Exchange(ref dbState._rqInCallback, 0);
}
}
catch
{
throw;
}
}
internal static void PollDatabaseForChanges(DatabaseNotifState dbState, bool fromTimer)
{
SqlDataReader reader = null;
SqlConnection sqlConn = null;
SqlCommand sqlCmd = null;
CacheInternal cacheInternal = HttpRuntime.CacheInternal;
bool flag = false;
Exception exception = null;
SqlException exception2 = null;
if (s_shutdown)
{
return;
}
if (((dbState._refCount == 0) && fromTimer) && dbState._init)
{
return;
}
if (Interlocked.CompareExchange(ref dbState._rqInCallback, 1, 0) != 0)
{
int num2;
if (fromTimer)
{
return;
}
HttpContext current = HttpContext.Current;
if (current == null)
{
num2 = 30;
}
else
{
num2 = Math.Max(current.Timeout.Seconds / 3, 30);
}
DateTime time = DateTime.UtcNow.Add(new TimeSpan(0, 0, num2));
do
{
if (Interlocked.CompareExchange(ref dbState._rqInCallback, 1, 0) == 0)
{
goto Label_00EA;
}
Thread.Sleep(250);
if (s_shutdown)
{
return;
}
}while (Debugger.IsAttached || (DateTime.UtcNow <= time));
throw new HttpException(System.Web.SR.GetString("Cant_connect_sql_cache_dep_database_polling", new object[] { dbState._database }));
}
Label_00EA:
try
{
try
{
Interlocked.Increment(ref s_activePolling);
dbState.GetConnection(out sqlConn, out sqlCmd);
reader = sqlCmd.ExecuteReader();
if (!s_shutdown)
{
flag = true;
Hashtable hashtable = (Hashtable)dbState._tables.Clone();
while (reader.Read())
{
string table = reader.GetString(0);
int num = reader.GetInt32(1);
string moniterKey = GetMoniterKey(dbState._database, table);
object obj2 = cacheInternal[moniterKey];
if (obj2 == null)
{
cacheInternal.UtcAdd(moniterKey, num, null, Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration, CacheItemPriority.NotRemovable, null);
dbState._tables.Add(table, null);
}
else if (num != ((int)obj2))
{
cacheInternal.UtcInsert(moniterKey, num, null, Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration, CacheItemPriority.NotRemovable, null);
}
hashtable.Remove(table);
}
foreach (object obj3 in hashtable.Keys)
{
dbState._tables.Remove((string)obj3);
cacheInternal.Remove(GetMoniterKey(dbState._database, (string)obj3));
}
if (dbState._pollSqlError != 0)
{
dbState._pollSqlError = 0;
}
}
}
catch (Exception exception3)
{
exception = exception3;
exception2 = exception3 as SqlException;
if (exception2 != null)
{
dbState._pollSqlError = exception2.Number;
}
else
{
dbState._pollSqlError = 0;
}
}
finally
{
try
{
if (reader != null)
{
reader.Close();
}
dbState.ReleaseConnection(ref sqlConn, ref sqlCmd, exception != null);
}
catch
{
}
lock (dbState)
{
dbState._pollExpt = exception;
if ((dbState._notifEnabled && !flag) && ((exception != null) && (dbState._pollSqlError == 0xafc)))
{
foreach (object obj4 in dbState._tables.Keys)
{
try
{
cacheInternal.Remove(GetMoniterKey(dbState._database, (string)obj4));
}
catch
{
}
}
dbState._tables.Clear();
}
dbState._notifEnabled = flag;
dbState._utcTablesUpdated = DateTime.UtcNow;
}
if (!dbState._init)
{
dbState._init = true;
}
Interlocked.Decrement(ref s_activePolling);
Interlocked.Exchange(ref dbState._rqInCallback, 0);
}
}
catch
{
throw;
}
}
